Highly Sensitive and Selective Photoelectrochemical Aptasensor for Cancer Biomarker CA125 Based on AuNPs/GaN Schottky Junction

Abstract

A gold nanoparticle (AuNPs)/gallium nitride (GaN) Schottky junction was fabricated by growing AuNPs in situ on the surface of GaN and then etched by H2O2 to appropriate diameter. The photogenerated electrons of GaN can be captured and transferred by the AuNPs to increase the migration efficiency, and the electron–hole pairs were separated, which results in the enhancement of the photoelectric performance of the system. The Fermi energy level of AuNPs and the charge transfer efficiency of the AuNPs/GaN can be adjusted by controlling the size of the AuNPs. Then the AuNPs/GaN Schottky photoelectrode had been applied to develop a novel photoelectrochemical (PEC) aptasensor for the epithelial ovarian cancer marker-CA125 detection. The DNA aptamer of CA125 was modified on the surface of the AuNPs via Au–S bonds. The aptamer can bind with the target with high selectivity, and the photoelectron transfer process of the system can be blocked by the protein, which results in the decrease of the photocurrent of the system. The ratio of photocurrent before and after incubation with CA125 (I 1/I 0) has a linear with the concentration of CA125 in the range of 1–100 U/mL with a detection limit of 0.3 U/mL. The standard addition recovery rates were between 86.01% and 90.09%. This method showed good sensitivity, selectivity, and reliability in detecting CA125 in serum.

Aptamer Nanomaterials for Ovarian Cancer Target Theranostics

“…Aptamers can also be used to create photoelectrochemical aptasensors. Hu et al developed an AuNPs/GaN Schottky photoelectrode to detect the ovarian cancer biomarker, CA125 ( Hu et al, 2020 ). In this design, AuNPs/GaN Schottky junctions were grown in situ on the GaN surface, and the DNA aptamer targeting CA125 was modified on AuNPs via Au-S bonds.…”

Applications of Aptamers in the Diagnosis and Treatment of Ovarian Cancer: Progress From 2016 to 2020

“…When CA125 combined with the aptamer/5-Fu complex, the complex separated from the surface of QDs, inducing a “turned-on” phenomenon attributed to the recovery of near-infrared photoluminescence. Hu et al (2020) grew AuNPs on a gallium nitride semiconductor via the Au-S bonds to fabricate a Schottky junction, then connected the aptamers targeting CA125 with the AuNPs via Au-S bonds. When the aptamers bound CA125, the photoelectron transfer process of the system was stopped, causing the photocurrent of the system to decrease.…”

2D MOF-Based Photoelectrochemical Aptasensor for SARS-CoV-2 Spike Glycoprotein Detection

“…For example, appropriate design, doping, and combining semiconductors with metals or other semiconductors to form heterojunctions have been applied to boost the photon-to-electricity conversion efficiency. 37 , 39 − 44 Among them, the Schottky junctions formed by metal and semiconductor have been paid much attention to for improving the photoelectrical conversion performance due to the enhancement effect of plasmon. 37 , 45 − 50 However, the developed PEC sensors still face some serious problems, such as relatively low photocurrent conversion efficiency and intolerance to photobleaching, which greatly limits their applications.…”

“… 37 , 39 − 44 Among them, the Schottky junctions formed by metal and semiconductor have been paid much attention to for improving the photoelectrical conversion performance due to the enhancement effect of plasmon. 37 , 45 − 50 However, the developed PEC sensors still face some serious problems, such as relatively low photocurrent conversion efficiency and intolerance to photobleaching, which greatly limits their applications. 36 , 42 Therefore, to meet the specific aims, it is necessary to develop proper photoactive materials with high photocurrent conversion efficiency and stable photocurrent.…”